Defense hormones guide plant roots’ mix of microbes
Salicylic acid attracts some bacteria, repels others, study finds
![roots of a weed called Arabidopsis thaliana](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/07/ti_root-microbiome_free.jpg?fit=860%2C460&ssl=1)
ROOT BOUND The roots of a weed called Arabidopsis thaliana (shown) make a hormone called salicylic acid. That hormone attracts some bacteria to the roots while shooing others away.
HermannFalkner/sokol, Flickr (CC BY-NC-SA 2.0)